A leadframe may be electrically coupled to an integrated circuit during an aspect of the fabrication of an electronic component. Methods for coupling the leadframe to the integrated circuit include wire bonding such as ball bonding or wedge bonding. The leadframe, integrated circuit, and bond wire may be encapsulated by a plastic molding process to form a package.
Bonding with bonding wire entails securing a bonding wire between a contact or a bond pad on an integrated circuit and a bonding site or target on a lead tip of a lead or lead finger on a leadframe. As the distances between bond pads on integrated circuits are reduced, the size of the integrated circuit die can be reduced while producing substantially equal performance and using less silicon.
Many leadframe manufacturing processes have a limit on the minimum width of the metal lead and the distance between leads that can be produced. To accommodate the smaller distances between bond pads, the bonding sites on the leads have become more remote from the semiconductor die as the die size has been reduced. To provide for closer leads or more dense leads at the same distance, three-dimensional leads have been developed. For example, U.S. Pat. No. 4,987,473, entitled Leadframe System with Multi-Tier Leads, discloses lead tips that have been bent upwards and some bent downwards into different planes to provide for denser packaging of lead tips without fear of electrical shorts. The '473 Patent does not disclose or teach efficient methods of manufacturing multi-level leads or an efficient bonding technique.
Three-dimensional leads have also been utilized in an effort to minimize wire crossing and shorting during the fill process of packaging a semiconductor chip. For example, U.S. Pat. No. 5,530,281, entitled Wire Bond Lead System with Improved Wire Separation, discloses a leadframe with three-dimensional leads for this purpose. The '281 Patent does not, however, disclose an efficient method for making leads or for bonding to such leads.
As an aspect of applying bonding wires between lead tips and bond pads, a heating block may be used. For example, U.S. Pat. No. 5,558,267, entitled Moat For Die Pad Cavity in Bond Station Heater Block, which is incorporated herein for all purposes, shows, a heating block to assist with bonding. The heating block may be heated by a heater as is known in the art.